The present invention relates to a semiconductor device and a technology (a method) of manufacturing the semiconductor device and relates to, for example, a technology which is effectively applied to a trench gate type power transistor and a technology (a method) of manufacturing the trench gate type power transistor.
For example, a technology of forming an overhang-shaped side wall insulating film so as to cover an upper edge of a gate trench in an inactive region is described in Japanese Unexamined Patent Application Publication No. 2013-232533.